The present invention relates to an agent for dosing aqueous systems with acrolein in concentrations effective as a biocide to prevent the growth of algae, aquatic weeds, and mucous. The present invention also concerns processes for producing such agents and a method of treating aqueous systems to control aquatic life by utilizing such agents.
Acrolein is a well-known biocide for treating liquids, particularly aqueous solutions in open and closed circulating systems containing muciferous microorganisms. The biocidal effectiveness of acrolein is directed to the prevention, regulation, and destruction of microorganisms in the group of bacteria, viruses, fungi, and algae; its high effectiveness permits acrolein of low concentrations to be used in water (U.S. Pat. Nos. 2,959,476 and 3,250,667, both of which are incorporated by reference in their entirety).
Due to its ability to quickly terminate photosynthesis, not only in algae but in larger celled aquatic weeds, and to thereby kill them, acrolein is used to combat weeds in water channels and to prevent the stoppage of pump systems. In addition, for years it has been a proven interceptor of hydrogen sulfide since it can both irreversibly bind H.sub.2 S and eliminate the source of H.sub.2 S by killing sulfate-reducing bacteria (e.g., Desulvovibrio desulfuricans).
Despite the high biocidal effectiveness of acrolein, its hazardous properties work against a broad application. Acrolein is poisonous and toxic when inhaled, causes choking and tearing, and is slightly flammable (flash point -29.degree. C., boiling point 53.degree. C.), which makes its handling difficult and expensive. Moreover, the contamination of acrolein with impurities also creates the danger of explosive polymerization. There has been no lack of proposals to reduce the potential hazard posed by contact with acrolein.
U.S. Pat. No. 4,851,583 suggests the use of an acrolein acetal instead of acrolein and the catalytic hydrolysis of acrolein acetal into acrolein. This process is not suitable for dosing flowing water since it would rapidly result in the contamination or deactivation of the employed ion exchanger.
DE 40 38 471 (U.S. Pat. No. 5,183,944) describes a process in which acrolein is released from cyclical acetals through the addition of a protonic acid with the simultaneous application of heat and reduced pressure or the introduction of nitrogen. Acrolein is removed in gaseous form and is introduced in that form into the medium being dosed out. DE 43 26 575.8 discloses an embodiment for dosing irrigation channels through the use of an acrolein acetal which does not rely on the availability of electronic of energy.
All prior art processes for dosing aqueous systems on the basis of an acrolein acetal also have the disadvantage that acetal, which is produced from acrolein, is considerably more expensive than acrolein.